SI-29 IMAGING OF SILICONE BREAST IMPLANTS AND INTRAOCULAR SILICONE OIL

Silicon-29 (Si-29) imaging was investigated as a potential imaging mod ality for monitoring silicone prostheses in humans. The Si-29 relaxati on times of several silicone gels were measured and found to average T -1 = 21.2 +/- 1.5 s and T-2 = 207 +/- 40 ms, with no significant diffe rence between virgin and explanted gels. A single-shot half-fourier ra pid acquisition with relaxation enhancement (RARE) and a refocused gra dient-echo sequence were used for acquiring Si-29 images with 5 x 5 mm (2) resolution and no slice selection. Three volunteers with silicone- gel-filled breast implants and one subject with an intraocular silicon e oil injection were thus examined in a total acquisition time of 10-1 5 min per image. On all Si-29 images, the shape of the silicone object was well depicted. Although at present, conventional proton images ar e superior in resolution and signal-to-noise ratio, Si-29 imaging has the advantage of optimal specificity, since only the silicone itself i s visible.